There's another puzzle in the essay. The 'devotees' and 'supporters' of Arendt appear to be academic philosophers. If this is so, however, part of Jacoby's argument starts looking a little strange. He argues:
So Arendt's two most famous books make opposite points, since she never reconciled them. Her minions pussyfoot around the contradiction or pedantically try to harmonize the notion of radical and banal evil. Others are less docile. Gershom Scholem, the scholar of Jewish mysticism, protested in a letter to her that her totalitarian book had offered a "contradictory" thesis to her Eichmann report: "At that time, you had not yet made your discovery, apparently, that evil is banal." Arendt agreed: "You are quite right: I have changed my mind and do no longer speak of 'radical evil.'" Her honesty is refreshing but damns her Origins study. It means that her most important book — the Eichmann report — stands unique in her oeuvre; it is not only her least philosophical book, but its notion of evil undermines the theory of her previous work.
I don't know what 'least philosophical' is supposed to mean here (certainly Eichmann in Jerusalem is the work that is most discussed in the philosophical mode as well as in other modes), but setting that aside, there is nothing bad or problematic or even unusual about someone coming to a different conclusion in one book than they did before. Jacoby tries to make a case of this, by saying that her 'supporters' -- undefined but apparently including Richard Bernstein -- 'lack her own forthrightness' and 'try to paper over the fissure'. But Bernstein, Jacoby's example, doesn't really suggest this. After all, Bernstein is a philosopher, and, while Arendt's own opinion of the relation between her two works has some weight, his primary interest is always going to be not Arendt's opinion of the relations among her works but their actual relations. It could very well be that Arendt was wrong to concede so much to Scholem. Arendt has a privileged position when it comes to interpreting her arguments, of course, but it's radically naive to think she has an incorrigible one. People forget details of arguments -- yes, even of their own arguments; they can be misled or confused by the language they use to convey an argument into thinking they're committed to A when really they're just committed to the vaguely similar but different A'; they can give two related arguments without seeing their connection; and so forth. Jacoby apparently considers this point, but he consigns it to the same sort of 'lack of forthrightness' without any argument.
Moreover, the primary interest in work like Arendt is not whether it is right, but whether it makes an interesting argument worth thinking about. If our concern is with what's right, either the earlier work, or the later work, or neither has to be right; and we just focus on that. But if our concern is with what's worth thinking about, then either or both could be wrong, or they both could contradict each other, and still be worthy of our interest. Part of philosophy is dialectical -- opposing arguments and opposing positions -- and a great deal of the interest of Eichmann in Jerusalem is due to the fact that, far from standing alone, it overcomes the arguments of the earlier work by a close philosophical case study.
All in all, it's a very puzzling essay. As I said, I'm certain that I'm missing something; Jacoby clearly has particular people, or at least particular groups of people, in mind. It's just hard to say who, and without knowing who, there's very little to do but be mystified by why he thinks his argument shows that Arendt is only famous as a political philosopher because she has no competition. (When he actually considers the competition, for instance, he mysteriously restricts, momentarily, the field to American political philosophy, which would eliminate, say, Jurgen Habermas or Simone Weil or Charles Taylor; he doesn't consider Noam Chomsky who, whatever else may be said of him, doesn't vanish into technical details and is far more popularly known than Arendt ever has been; he doesn't seem to include any feminist philosophers -- for instance, he mentions Sartre but ignores Simone de Beauvoir. Are there reasons for this? I do not know; if so, they are not given.)